/* C2C / TaH / R2R research page primitives. Also used by new-project templates. */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Text', 'SF Pro Display', 'Helvetica Neue', Arial, sans-serif;
  font-size: 17px;
  line-height: 1.47059;
  font-weight: 400;
  letter-spacing: -0.022em;
  color: var(--apple-black);
  background: #fff;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: all 0.8s ease;
}

.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 100px 24px 80px;
  background: linear-gradient(180deg, #fff 0%, var(--apple-light-gray) 100%);
  position: relative;
  overflow-x: hidden;
}

.hero-badge:hover {
  background: var(--apple-blue);
  color: #fff;
}

.hero-title {
  font-size: clamp(48px, 8vw, 96px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.045em;
  margin-bottom: 16px;
  padding: 0 10px;
  animation: fadeInUp 0.8s ease-out 0.1s backwards;
}

.hero-subtitle {
  font-size: clamp(21px, 3vw, 28px);
  font-weight: 400;
  color: var(--apple-gray);
  max-width: 680px;
  margin: 0 auto 40px;
  line-height: 1.38;
  animation: fadeInUp 0.8s ease-out 0.2s backwards;
}

.hero-stats {
  display: flex;
  gap: 60px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 48px;
  animation: fadeInUp 0.8s ease-out 0.3s backwards;
}

.stat-item {
  text-align: center;
}

.stat-label {
  font-size: 14px;
  color: var(--apple-gray);
  margin-top: 4px;
}

.section {
  padding: var(--section-padding);
}

.container-wide {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 24px;
}

.section-eyebrow {
  font-size: 14px;
  font-weight: 600;
  color: var(--apple-blue);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 8px;
}

.section-title {
  font-size: clamp(32px, 5vw, 56px);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: 21px;
  color: var(--apple-gray);
  max-width: 600px;
  line-height: 1.38;
}

.section-dark .section-subtitle {
  color: rgba(255, 255, 255, 0.7);
}

.section-dark .text-highlight-gradient {
  background: linear-gradient(135deg, #a78bfa 0%, #c084fc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.authors-section {
  text-align: center;
  padding: 80px 0;
}

.problem-visual {
  margin: 60px 0;
  text-align: center;
}

.problem-diagram {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 40px;
  flex-wrap: wrap;
  margin: 40px 0;
}

.problem-box-icon {
  font-size: 40px;
  margin-bottom: 16px;
}

.problem-box h4 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 8px;
}

.problem-box p {
  font-size: 14px;
  color: var(--apple-gray);
}

.insight-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 60px;
}

.insight-card:hover {
  background: rgba(255, 255, 255, 0.08);
  transform: translateY(-4px);
}

.insight-percentage.green { color: #30d158; }

.insight-percentage.blue { color: #0a84ff; }

.insight-percentage.orange { color: #ff9f0a; }

.insight-desc {
  font-size: 14px;
  color: rgba(255, 255, 255, 0.6);
  line-height: 1.5;
}

.expandable-section {
  margin: 24px 0;
  border-radius: 16px;
  overflow: hidden;
  background: #fff;
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.04);
  transition: box-shadow 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.expandable-section:hover {
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.08);
}

.expandable-section.open {
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.1);
}

.expandable-header {
  padding: 24px 32px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
}

.expandable-header::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 0;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  transition: width 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  opacity: 0.1;
}

.section-dark .expandable-section .expandable-header:hover {
  background: rgba(255, 255, 255, 0.1);
}

.expandable-title {
  font-size: 17px;
  font-weight: 600;
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.expandable-icon {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--apple-light-gray);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.expandable-section.open .expandable-icon {
  transform: rotate(45deg);
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.expandable-section.open .expandable-icon i {
  color: #fff !important;
}

.expandable-content {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.expandable-inner {
  padding: 0 32px 32px;
  opacity: 0;
  transform: translateY(-10px);
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1) 0.1s;
}